Wet weather is in store for Northern California through the middle of next week, but Halloween should be dry for trick-or-treaters, according to the National Weather Service.

Rain began falling late Thursday, but the first of several rounds didn’t make its presence truly known until after midnight Friday. As of 6 a.m. Friday, Woodland had recorded .56 inches of rain.

As of Friday morning, Woodland’s official rain collection station at the UC Cooperative Extension Service on Cottonwood Street had recorded 1.21 inches over the preceding 24 hours. That brought to 1.81 inches since July 1 of 2015, which compared to .10 inches for the preceding year. The 10-year seasonal average for Woodland is 1.22 inches.

The storm system advancing from south to north toward the West Coast is drawing some moisture from Hurricane Seymour, located in the Pacific Ocean south of the southern tip of Baja California.

Unlike the system Monday, which dropped rain primarily north, this system is expected to soak the entire region, from Santa Rosa to Sacramento and points south.

Some of the heaviest rains are expected in coastal Monterey County, and a flash flood warning is in effect for the burn area from the Soberanes fire, which torched more than 132,000 acres. The weather service is warning that rainfall rates in excess of a half-inch per hour are possible in that area, and these heavy downpours could result in debris flows and flash flooding.

Unsettled weather with periods of rain is projected through Wednesday, but trick-or-treaters more than likely won’t need umbrellas Monday night, California is still substantially in a drought, but don’t call it parched. A year ago, almost the entire state was in severe, extreme or exceptional drought — from the Oregon state line to the Mexican border — but since then enough rain has fallen that a chunk of northwestern California is now back to normal and the worst levels of drought designation have retreated somewhat to the central and southern regions, according to the U.S. Drought Monitor.

Some north coast points are hundreds of percent above normal rainfall so far in the “water year,” a period of time in which rainfall totals are measured, that began Oct. 1. At midweek, Crescent City had received 14.01 inches compared with the normal 3.11 inches to date. Since Jan. 1, the total was more than 46 inches.

As a river of atmospheric moisture began bringing more rain to parts of the state Thursday, the forecast was significant enough to turn attention to the threat of flash floods and debris flows from thousands of acres scorched by numerous wildfires — especially from the Central Coast south to the Los Angeles region, which remains in the grip of exceptional drought.

Still, there was doubt about how just how wet Southern California would get.

“Lots of moisture headed our way, but still some uncertainties as to how much of that will reach the ground,” the area weather service office wrote.

Other storms are expected to follow during the weekend, with potential for snow in sections of the Sierra Nevada, which normally stores a huge amount of the state’s water supply in the form of a winter snowpack that eventually runs off into major reservoirs.

After five years of drought, it’s uncertain how much snow to expect in the current water year.

When the 2016 water year ended on Sept. 30, the California Department of Water Resources summarized it as a “snow drought,” with “meager precipitation that fell more often as rain than snow” even though parts of the north had average or above-average precipitation.

That occurred during a strong El Niño, the periodic warming of the equatorial Pacific that sometimes brings heavy precipitation to California. Now, federal forecasters see a nascent La Nina, an ocean cooling phenomenon linked to drier-than-normal conditions in California.

According to the state Department of Water Resources, in 18 La Nina winters since 1950-51, above-average precipitation occurred 11 times in the northern Sierra and eight times in the central and southern Sierra. In Southern California, La Nina winters brought below-average precipitation to the coastal region 16 times and 15 times in the region’s interior.